Street traffic control system



NOV 3, 942- E. J. COLLE 2,300,613

STREET TRAFFIC CONTROL SYSTEM Filed May s1. 193s "LIGHT PHTO ELECTE /CCE' L L5 Bf@ L/s/fr sou/ac:

Patented Nov. 3 1942 T OFFICE STREET TRAFFIC CONTROL SYSTEM EdouardJoseph Colle, Antwerp, Belgium, assignor to International StandardElectrlcrCorporation, New York, N. Y. l

' Application May 31, 1939, serial No. 276,628 In Belgium June 4, 1938 1claim. (ci. 177-337) The invention relates to improvements in orrelating to street trailic control equipment of the trado-actuated type.4 Previous systems of traio operated control equipment comprised roadcontacts or studs embedded in the roadway near a crossing, thesecontacts or studs being operated each time a vehicle passed over them.Upon the operation of a contact an impulse is transmitted to acontroller which registers the number of vehicles passing towards thecrossing over each roadway leading thereto and so determines how thetrafic lights are to be operated. A

Such systems have the disadvantage that the detectors embedded in thesurface of the road are subject to heavy wear and consequently have tobe frequently renewed.

The object of the invention is to provide a trafc operated system whichis not subject to heavy wear due to the passage of trafc over essentialparts of the control system.

According to the main feature of the invention each roadway leading to acrossing is provided with two light-sensitive cells which are mounted ata short distance apart on one side of the roadway, are arranged to beactuated by beams of light directed on to them from a lamp or lampsmounted on the opposite side of the roadway, and'control recording meansarranged to differentiate between interruption of the lightbeams indifferent ways. It is to be understood thatthe terms light andlight-sensitive devices are to be interpreted as including infrared raysand devices responsive thereto.

The invention will be fully understood from the following description ofthe accompanying drawing which shows a four-road crossing provided withfour sets of signals and four sets of tramc-operated control equipment.

The sets of equipment associated with each roadway are identical and theoperation of one set of equipment only will bedescribed in detail.

Situated on the right hand side of the road A approaching the crossingis a lamp standard AL which may comprise either a single lamp arrangedto direct beams of light on to each of the photo-electric cells mountedat PAI and PA2 o r two lamps each of which is arranged to direct a beamof light on to either PAI or PA2. .The lamp and cells are mounted atsuch a height above the ground that when a vehicle passes along theroadway the beams of light impinging on the photo-electric cells areinterrupted.

'Ihe arrangement of the photo-electric cells the right hand side of theroadway will interrupt both the beams of light for a period whilstvehicles passing along the left hand side of the road will interruptfirst one beamfof light and then the other beam of light but will notinterrupt both beams at any one time. In this manner the position of thevehicle with respect to the width of the road is determined. l

Each photo-electric cell is arranged to control a relay in a chain ofrelays at the traffic control cabinet TCC.

If the relays controlled byphoto-electric cells PAI and PA2 are operatedsimultaneously then the traiilc controlling register device at TCCregisters the fact that avehicle has passed along road A towards thecrossing. If, however, the relays controlled by PAI and PA2 do notoperate simultaneously it is not possible to operate the register deviceand hence vehicles proceeding along the side o the road opposite to thelamp do not eiect the controller.

Vehicles proceeding towards the crossing along the other roadwaysleading to the crossing, ef,- fect the photo-sensitive devices BL, PBI,FB2; CL, PCI, PC2, and DL, PDI, PD2 associated with these roadways inlike manner and according to the ow of traffic along the roads thetraftlc lights TLA, TLB, 'I'LC and TLD are operated.

If it is not possible to arrange the lamp and photo-electric cells tohave a large angle between the beams directed across the roadway, therelays controlled by the photo-electric cells can be so interconnectedthat the order in which the beams of light are interrupted determineswhether the register device makes a record of a vehicle passing towardsthe crossing or not. For example a vehicle passing along the right handside of the road towards the crossing will rst interrupt the beam oflight between AL and PAI and then the beam of light between AL and PA2.This order of interruption of the light beams ensures that the vehicleis registered as proceeding towards the crossing. If, however, a vehiclepasses on the right hand side of the roadway away from the crossing thenthe beam of light between AL and PA2 is first interrupted followed bythe beam of light between AL and PAI. This order of interruption isarranged to have no effect on the register device.

Both the housings for the lamps and the photo-electric cells areprovided with screens arranged to prevent daylight and direct beams oflight, due to the sun or due to car headlights,

and lamp is such that a vehicle passing along tem.

from interfering with the operation of the sysphoto-sensitive devices toproduce dverging beams of light falling on respective ones of saidphoto-sensitive devices, and a relay operative in response tointerruption of both of said beams of 5 light during the same interval,whereby vehicles passing said light source on the side of the streetadjacent thereto will operate said relay, while vehicles passing saidlight source on the side of the street adjacent said photo-sensitivedevices 10 will not affect said relay.

EDOUARD JOSEPH COLLE.

